Apparatus for fluid propulsion by vibratory diaphragms



H. C. HAYES Sept. 24, 1929.

APPARATUS FOR FLUID PROPULSION BY VIBRATORY DIAPHRAGMS Filed Oct. 23,1926 r f/IIII/IIIIIIIIIIIIIIIIIIIAZ'IIIl/I\\ I INVENTOR.

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Patented Sept. 24, 1929 UNITED STATES HARVEY C. HAYES, OI WASHINGTON,DISTRICT OF COLUMBIA APPARATUS FOR FLUID BBOPULS ION BY VIBRATORYDIAPHRAGMS Application filed October 23, 1926. Serial No. 143,776.

(GRANTED UNDER THE ACT OF IAROE 3, 1883, AS AMENDED APRIL 30, 1928; 3700. G. 757) My invention relates broadly to fluid propulsion by means ofvibratory diaphragms.

The object of my invention is to provide a means for imparting kineticenergy to a fluid by means of a vibratory diaphragm,

for the production of mechanical work.

My invention consists substantially in the construction, combination andarrangement of parts associated therewith or as will be more fullyhereinafter set forth as shown by the accompanying drawings and finallypointed out in the appended claims.

Reference is to be had to the accompanying drawing forming a part ofthis specification,

in which like reference characters indicate corresponding partsthroughout the several views and in which Figure 1, represents adiagrammatic view of my electromagnetic pump, showing the manner inwhichl have controlled the output of the energy of the diaphragm whenenergized by an alternating current,

Figure 2 represents a modification thereof in which I have used a shieldto control the i flow of fluid through the pump,

Figure 3 shows my device as applied to power generators, and

Figure 4 is a detail sectional view through a small model of myelectromagnetic pump showing the detailed construction thereof.

Referring to Figure 1, when the diaphragm 1, is set into motion by afluctuating or alternating electrical current through coil 2, theportion of the medium in which the instrument is placed and that whichis contained within the outlet 3 is forced outwardly from the outlet asthe diaphragm 1 moves away from the coil 2 and toward the orifice in thecasing. This movement of the diaphragm will hereinafter be termed thepumping stroke of the diaphragm.

When the diaphragm moves toward the coil 2 and away from the outlet 3afresh portion of the medium in which the electromagnetic pump is placedis taken into' the chamber between the diaphragm and the easing, sincethe momentum of the fluid which was produced by the pumping stroke ofthe diaphragm carried that portion of the medium away from the outlet 3.This movement of the diaphragm will hereinafter be termed the intakestroke of the diaphragm.

As the frequency of the current passing through the-coil 2 increasesthere appears a distinct and well defined flow of the medium, havingconsiderable velocity, directed outwardly from the outlet 3.

This effect becomes especially marked when the frequency of theelectrical current is equal to the natural free period of the soundgenerating diaphragm.

This action is diagrammatically shown in Figure 1, wherein the shadedarea 5 re resents a compressed portion of the medium ejected from theoutlet 3 by the motion outward of diaphragm 1. When the diaphragm isthen attracted inwardl by the magnet 2, some of the outside medium isdrawn back into the sound reproducing chamber to replace that which wasexpelled. This operation is repeated each time the diaphragm oscillateswith the result that as the frequency of the current passing through thecoils 2 approaches the resonant frequency of the diaphragm there isproduced a rapid series 0 impulses 5 which are directed out wardly intothe medium surrounding the pump and a series of periodical influxes 4 ofthe medium into the chamber in front of the diaphragm, the two seriesalternating with each other as the diaphragm moves throu h its pumpingand intake strokes.

The l1ne 6 designates the direction of flow of the fluid as it entersthe chamber in front of the diaphragm 1, and line 12 designates theoutward flow of compressions 5.

Tests carried out on the sim le device described, have shown that its eciency, when the current fluctuations are timed to the natural period ofthe diaphragm, is unusually high and the effectiveness of the device islargely dependent upon a proper dimensioning of the sound chamber andthe outlet.

The applicant has also found that the motion of the medium about theoutlet 3 is not a simple inward flow as represented by the vector (6)but is really avortex ring wherein the direction of whorl is shown by 7.This vortex motion of the medium prevents it from entering the chamberas readily as it otherwise would and as a result the pumpingeflectiveness is increased by providing a secondary nozzle, one form ofwhich is shown by numeral 8 in Figure 2.

The outward motion of the medium may be utilized by pivoting before theoutlet 3 a wheel 9 carrying vanes 10 about its periphery as shown inFigure 4 or by placing a small turbine wheel 11 in front of the outletas shown in Figure 5. In either case the wheel will be found to rotatewith a speed and vigor entirely unlooked for when the small amount ofelectrical energy required to operate the electromagnetic pump isconsidered.

The apparatus shown in Figures 3.and 4. for absorbing the kinetic energyimparted to the fluid by the vibrations of the diaphragm is diagrammaticonly as I do not wish to limit myself to the specific devices showntherein since the kinetic energy imparted to the fluid is equallyapplicable to the propulsion of ships as it is to driving devicesactuated by the flow of a fluid impinging upon the moving parts of thosedevices.

As shown in detail in Figure 4 a small model of the electroma netic pumpconsists of a casing 13 against t e outer flanged surface 14 of which isclamped the diaphra m 1 by means of a cover or outlet casing 15 w ich isfirmly secured to the casing 13 by means of screws 16 which are threadedinto the flange of the casing 13.

Within the casin 13 is mounted a permanent magnet 17 t e poles 18 ofwhich extend to points in close proximity to the diaphragm 1 butwhich'are sufi'iciently removed therefrom that the diaphragm will nottouch the poles when in its maximum displacement. Upon each of the polesof the permanent magnet 17 are Wound the coils 2 which are supplied withalternating current from the terminals of the electrical system of thepump as indicated at 19.

Between the diaphragm 1 and the interior of the casing 15 I haveprovided a chamber 20 from which leads the outlet 3. In order that thepump will operate with a maximum efficiency the radius of the outlet 3and the length of the tube thereof, both theory and practice, indicatethat the volume of the outlet must equal the volume displaced by themovement of the diaphragm from one position of maximum displacement tothe other position of maximum displacement. This condition isapproximated by the equation-v respect to the radius (R) so that theterm tvaaeve may be neglected as exceedingly small in comparison to thevalue of With such an approximation the simple equation is aR =T L Thissimple equation serves with suficient accuracy to design theelectromagnetic pump.

In the model that I have constructed the driving force of the coils 2 issuch that the displacement of the diaphragm 1 at its center is 1/100inch whenthe coils are energized by an alternating current of a freqencywhich approximates the resonant frequency of the diaphragm 1 and theradius of the diaphragm is 2 inches. Then the simple equation givenabove is 1/100X (2) 1/100''," L.

For any value of (7) then the corresponding value of (L) may bedetermined. Thus assuming (1') =1/4. inch, then L/16=4/l00 or L=64/ ofan inch.

These different values have been incorporated in the model as indicatedin Figure 6.

Further I do not wish to limit myself to the use of a particular fluidas the principles involved apply in the same way irrespective of thefluid used, the difference lying only in the efficiency of operationwhich is dependent upon the compressibility and the viscosity of thefluid used.

It will be understood that the above description and accompanyingdrawings comprehend only the general and preferred embodiment of myinvention and that minor detail changes in construction and arrangementof parts may be made within the scope of the appended claims and withoutsacrificing any of the advantages of my invention.

The invention herein described may be manufactured and used by or forthe Government of the United States for governmental purposes withoutthe payment to me of any royalty thereon or therefor.

Having thus described my invention, What I claim is as follows:

1. In a fluid pump, the combination of a casing having an orifice forthe ingress and egress of a fluid to and from the casing, a vibratorydiaphragm the center of which is adjacent the orifice, andelectromagnetic means for producing a displacement of the diaphragm atits resonant frequency, the volume of said orifice computed from theequation substantially as described.

2. In a fluid pump, the combination of a casing having an orifice forthe ingress and Ill egress of a fluid to and from the casing, a

vibratory diaphragm the center of which is adjacent the orifice, andelectromagnetic means for producing a displacement of the diaphragm atits resonant frequency, the volume of said orifice computed from theequation aR =r L 4. In a fluid pump, the combination of a casing havinga conical interior surface and an orifice at the apex of said conicalsurface for the ingress and egress of a fluid to and from said casing, avibratory diaphragm within said casing and forming with said conicalsurface a conical chamber within said casing, the center of saiddiaphragm being located along the axis of said orifice, andelectromagnetic means for imparting vibrations to said diaphragm at itsresonant frequency to produce a flow of fluid through said orifice.

5'. In a fluid pump, the combination of a casinghaving a conicalinterior surface, a diaphragm within said casing and forming with saidconical surface a conical chamber within said casing, means forelectromagnetically driving said diaphragm and means permitting theingress and egress of a fluid to and from said conical chamber toproduce a directional flow of fluid away from said diaphragm in a linesubstantially perpendicular thereto. t

6. In a fluid pump, the combination of a casing having a conicalinterior surface, a diaphragm within said casing and forming with saidconical surface a conical chamber within said casing, means forelectromagnetically driving said diaphragm at its resonant frequency andmeans for permitting the ingress and egress of fluid to and from saidconical chamber to produce a directional flow of fluid away from saiddiaphragm in a line substantially perpendicular therto, said lastmentioned means being aligned substantially along the central axis ofsaid diaphra m.

HARVEY C. HA%'ES.

